1. Field of the Invention
The present invention relates to ink fountains for printing presses. In particular, the present invention relates to an apparatus for closing off an ink fountain when the printing press shuts down, to prevent leakage of ink from the fountain.
2. Description of the Prior Art
An ink fountain assembly in a printing press typically includes a fountain roll which rotates in a supply of ink. As the fountain roll rotates, it picks up ink from the supply of ink, then transfers this ink to other rolls in the printing press and ultimately to the printing plate and to the material to be printed. A typical fountain assembly also includes a fountain blade adjacent the fountain roll, extending along the axial extent of the fountain roll and spaced apart from the fountain roll by a small distance or gap. The fountain blade and the adjacent curved surface of the fountain roll form a chamber within which is maintained a reservoir of ink. The gap between the blade and the roll is adjustable to control the amount of ink which is retained on the fountain roll after it rotates through the ink supply and before it contacts the next roll in the press. The gap is adjusted by a series of ink keys which move respective sections of the blade toward or away from the roll to vary the gap between the individual sections of the blade and the roll, thus forming an ink film having a desired thickness profile on the roll.
When a printing press is shut down, this gap between the fountain blade and the fountain roll must be closed in order to prevent ink from leaking out of the fountain. The gap is usually closed by moving the fountain blade so that it is disposed against the fountain roll, along its entire length. This is done by closing each of the ink keys spaced along the blade. If every ink key is closed down completely, the entire length of the blade is moved against the roll, thus closing the gap as desired.
Closing the gap by closing all the ink keys, however, can be time-consuming. Also, whatever settings the keys were at before closing, is lost, and all the keys must be reset once the press is started up again.